1. Field of the Invention
The present invention relates to a rotor of a salient-pole type rotary machine in which a coil brace is disposed between adjacent magnetic poles to hold field coils.
2. Description of the Prior Art
FIG. 1 shows a partial sectional view of a conventional rotor of a salient-pole type rotary machine which is disclosed, for example, in Japanese Utility Model Publication No. 8355/82. In the same figure, numeral 1 designates a magnetic pole; 2,a pole insulator applied to the magnetic pole 1; 3,a field coil; 4, a spacer; 5, a coil brace for pressing the field coil 3; 6, a bolt for fixing the coil brace 5; 7, a coil brace insulator for isolating the field coil 3 and the coil brace 5 from each other; and 8, a spider for holding the magnetic pole 1.
The operation of such conventional rotary machine will now be described. When the bolt 6 is tightened, the coil brace 5 presses and fixes field coils 3 to magnetic poles 1 through coil brace insulators 7. Further, by means of spacers 4 the field coils 3 are pushed and fixed to the shoulders of the magnetic poles 1.
The conventional rotor of a salient-pole type rotary machine is constructed as above, so at the time of fabrication of the rotor it is necessary to make adjustment and machining of the abutment surfaces of coil brace and coil brace insulator and that of the abutment surfaces of spacer and spider, field coil. Besides, for the correction of dimensional changes caused by secular ageing of the insulating material it is necessary to disassemble the machine, pull out the rotor, then make additional tightening of bolts and re-adjustment of spacers. Further, when field coils expand thermally due to rise of the temperature during operation of the machine, the coil brace presses the field coils, thus causing deformation of the coils.